scholarly journals Bridging inertial and dissipation range statistics in rotating turbulence

2020 ◽  
Vol 32 (9) ◽  
pp. 095104
Author(s):  
Shailendra K. Rathor ◽  
Manohar Kumar Sharma ◽  
Samriddhi Sankar Ray ◽  
Sagar Chakraborty
Keyword(s):  
Rotating Turbulence ◽  
Dissipation Range

Energy spectrum in the dissipation range

2018 ◽  
Vol 3 (8) ◽  
Author(s):  
Sualeh Khurshid ◽  
Diego A. Donzis ◽  
K. R. Sreenivasan
Keyword(s):  
Energy Spectrum ◽  
Dissipation Range

scholarly journals Anisotropic energy transfers in rotating turbulence

2011 ◽  
Vol 318 (4) ◽  
pp. 042005
Author(s):  
Cyril Lamriben ◽  
Pierre-Philippe Cortet ◽  
Frédéric Moisy
Keyword(s):  
Rotating Turbulence ◽  
Anisotropic Energy ◽  
Energy Transfers

Scale-dependent alignment, tumbling and stretching of slender rods in isotropic turbulence

2018 ◽  
Vol 860 ◽  
pp. 465-486 ◽  
Author(s):  
Nimish Pujara ◽  
Greg A. Voth ◽  
Evan A. Variano
Keyword(s):  
Isotropic Turbulence ◽  
Fluid Velocity ◽  
Inertial Range ◽  
Small Scale ◽  
Strain Rate Tensor ◽  
Scaling Exponents ◽  
Slender Body Theory ◽  
Velocity Statistics ◽  
Rigid Rods ◽  
Dissipation Range

We examine the dynamics of slender, rigid rods in direct numerical simulation of isotropic turbulence. The focus is on the statistics of three quantities and how they vary as rod length increases from the dissipation range to the inertial range. These quantities are (i) the steady-state rod alignment with respect to the perceived velocity gradients in the surrounding flow, (ii) the rate of rod reorientation (tumbling) and (iii) the rate at which the rod end points move apart (stretching). Under the approximations of slender-body theory, the rod inertia is neglected and rods are modelled as passive particles in the flow that do not affect the fluid velocity field. We find that the average rod alignment changes qualitatively as rod length increases from the dissipation range to the inertial range. While rods in the dissipation range align most strongly with fluid vorticity, rods in the inertial range align most strongly with the most extensional eigenvector of the perceived strain-rate tensor. For rods in the inertial range, we find that the variance of rod stretching and the variance of rod tumbling both scale as $l^{-4/3}$, where $l$ is the rod length. However, when rod dynamics are compared to two-point fluid velocity statistics (structure functions), we see non-monotonic behaviour in the variance of rod tumbling due to the influence of small-scale fluid motions. Additionally, we find that the skewness of rod stretching does not show scale invariance in the inertial range, in contrast to the skewness of longitudinal fluid velocity increments as predicted by Kolmogorov’s $4/5$ law. Finally, we examine the power-law scaling exponents of higher-order moments of rod tumbling and rod stretching for rods with lengths in the inertial range and find that they show anomalous scaling. We compare these scaling exponents to predictions from Kolmogorov’s refined similarity hypotheses.

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